add test for isElementInView

Author: jscottsmith

__tests__/isElementInView.test.js

@@ -0,0 +1,24 @@
+import isElementInView from 'utils/isElementInView.js';
+
+const element1 = {
+    attributes: {
+        top: 0,
+        bottom: 500,
+    },
+};
+
+const element2 = {
+    attributes: {
+        top: 2500,
+        bottom: 4000,
+    },
+};
+
+const windowHeight = 1000;
+
+test('Returns whether an element is in view', () => {
+    expect(isElementInView(element1, windowHeight, 1500)).toBe(false);
+    expect(isElementInView(element1, windowHeight, 0)).toBe(true);
+    expect(isElementInView(element2, 4000, 0)).toBe(true);
+    expect(isElementInView(element2, windowHeight, 6500)).toBe(false);
+});